was I not supposed to...

[navi tasan]

1) Was I not supposed to help him with his homework?

Isn't that sentence ambiguous?

I think it could mean two things:

a) Wasn't I supposed to help him with his homework? (I thought I was. Well, I am happy that I did anyway. He needed it.)
b) Was I supposed not to help him with his homework? (I am sorry that I did. I made a bad mistake.)

'a' and 'b' seem unambiguous to me.

Gratefully,
Navi.

 

[teechar]

Without further context, it's more likely to imply "b."

 

[GoesStation]

This one is genuinely ambiguous without context. Intonation would make it clear in speech.

 

[Tdol]

I agree about the intonation- there is no way to me of knowing how the speaker feels without knowing how they said it.